Claude Francois Milliet Dechales

Born: 1621 in Chambéry, France
Died: 28 March 1678 in Turin, Italy

Dechales became a Jesuit at the age of 15 and was educated within the Jesuit Order. For a time he was a Jesuit missionary in Turkey.

Dechales lectured at Jesuit colleges, first in Lyon and Chambéry. From Chambéry he went to Marseilles where King Louis XIV appointed him Royal Professor of Hydrography. In Marseilles he taught navigation, military engineering and other applications of mathematics. From Marseilles he moved to Turin where he was appointed professor of mathematics.

Dechales is best remembered for Cursus seu mundus mathematicus , a complete course of mathematics. Topics covered in this wide ranging work included practical geometry, mechanics, statics, magnetism and optics as well as topics outwith the usual topics of mathematics such as geography, architecture, astronomy, natural philosophy and music.

The book was widely used but it reflects his ability to teach rather than a research ability and fails to use the mathematical advances of the day. It is old-fashioned in its coverage: in algebra, for example, it owes more to Diophantus than to the algebraists of its day.